Direct reading micrometer



Oct. 12, 1937. w. A. BOHN DIRECT READING MICROMETER Filed July 13, 1934 lllllllllllllllllll IIII 3 h/a/fer 50/? 6J4, gym- 4 9 2M;

Patented Oct. 12, 1937 I 1.. r

UNITED STATES PATENT OFEl CE Walter A. Bohn, Lakewood, Ohio, assignor to Master Products Company, Cleveland, Ohio, a V

corporation of Ohio Application July 13, 1934, Serial No. 734,964 5 Claims. -(Cl. 33147) This invention relates to micrometers, and The micrometer jaws, or points, comprise an particularly to those that are known in the trade, anvil Hi and a feeler in the form of a plunger H as the direct-reading type. Micrometers of this which are disposed in axial alignment. The ancharacter are used for'production work in gaugvil, or relatively stationary jaw I is rigidly ing large quantities of sheet metal with rapidity, mounted on the lower arm of a C-shaped bar I2,

particularly during the sorting operation, while the upper arm of which terminates in an extenthe metal is being transferred from a conveysion 9, that has a passageway I3 therein in which ance to a warehouse. the jaw II is slidably mounted. The rearward The usual C-clamp hand-operated micrometer end of the bar l2 has an extension M, rigid thereis objectionable for production work, as outlined, with, which operates as a handle for actuating 10- for it necessitates an objectionable length of time the micrometer. The mechanism for moving the to use it, and for the further reason that it can feeler ll comprises a finger grip bar l5 which is be sprung if excessive pressure is used on the pivotally mounted, at an intermediate point it, operating stem. An'effort has been made to proto the handle extension l4, and is pivotally conduce a direct-reading micrometer, but so far as nected at ll, to a yoke H3. The yoke shown com- 15 I am aware, none has been produced, in which prises a pair of plates that aredisposcd on each the jaws engage the work underhand pressure, side of the support l2 and are rigidly connected and in which'the same reading is obtained irth u h a pin to the feeler ii. A slot 2| respective ofthe pressure that is exerted. Furpermits the pin to be moved with reference to thermore, such micrometers have been more or the support l2; as may be observed from a com-- 20 less delicate devices, which would not withstand parisonof Figs. 1 and 2. careless handling by an operator. The micrometer indicator is shown, as com- An object of my invention therefore, is to make prising a pointer and a dial 26 which are a direct-reading micrometer in which the same ou ted W t n a cas The pointer is Suit- 3 reading may be obtained regardless of the presably attached by a mechanism, (not shown) to- 25 sure, Which is exerted by the operator, and in a stem 26, which is normally urged into contact which all of the delicate workingparts are enwith th upp e d of t feelel L and t e cased," and therefore fully protected against mechanism is So adjusted that when the stem is damage. in contact with the anvil the indicator registers 31 An additional objectis to provide a micrometer zero. The indicator and its associated internal in which the operating members exert a pulling mechanism may be pur h in Open market as distinguished from a, pushing force upon the so it need not be described in detail. It is sufmovable jaw, thus relieving the '0 support of ficient however, to point out that by means of an theusual stresses that tend to spring it apart. adjusting screw 30, the position of the casing with 3 In this connection my invention includes a conreference to the support I2 may be adjusted, and 35 struction in which the forces which act upon the then locked, so as to make the micrometer readfeeler and anvil occur on a' line that is coincident. ing zero whenever the feeler and anvil are in conwith the axes of the feeler and anvil, wherefore, tact. Thus,,compensation may be made for any the operator can detect, through his sense of Wear on the contacting points.

touch, whether or not the tool is being held at The normal position of the hand grips l4 and 40 right angles to the work. This is important, for I5, is illustrated in Fig. 1, in which the stem otherwise animperfect reading would be obtained. and, anvil are separated a maximum amount.

A further object of my invention is to make The hand grips are urged apart by a spring 3| a micrometer in which the wear on the points which is carried. by the finger bar I5 and bears may be taken up by means of an adjustment against the handle l4. Thus the micrometer is 45 mechanism, wherefore the points need not be acalways available for 1 If desired t e fin e curately machined. grip part l5 may have a scale 40 on the lower Referring now to the drawing, Fig. 1 is a side edge thereof to facilitate measurement of the elevation of a micrometer made in accordance sheets of metal that are being gaugedy In addiwith my invention; Fig. 2 shows a fragmentary o i desired, a gu d 4| may be mounted on 50 elevation similar to that-0f Fig. 1, but with the the pr je tion 9 o as t p t t th mi r meter feeler and anvil in contact with the work to be housing. gauged; Fig. 3 is a section taken on the line An important advantage of the present inven- 3 '3 in Fjg 1; Fig. 4, is top plan vi of th tion is the fact that regardless of the pressure,

. micrometer. V which is exerted against the work, such pres- 56 sure is not imparted to the delicate parts of the indicator. A clearance slot 45 between the support l2 and the handle I4 assures the prevention of stress transmission through the support.

A further advantage is the fact that the operating forces exert a pulling action on the feeler against the anvil, and that such forces are as near as possible in alignment with the axis of the feeler and anvil. Thus, there is no tendency to spring the support l2 as is the case in the customary threaded type of micrometer.

An additional characteristic of the present invention is the fact that the micrometer dial is disposed in a plane at substantially right angles to the axis of the feeler, thus the operator may make a pile of sheets and obtain a quick reading with minimum effort. In addition, the direct connection between the hand grip and the work engaging points enables an operator, by the sense of touch, to adjust the plane of the tool 'so as to insure proper positioning of the points with reference to the work. For example, if the tool is not exactly at right angles to the work, or if a small particle is lodged between the work and the points, such condition can be felt through the hand of an operator and the tool can be quick- 1y turned to the proper position. Furthermore, if the foreign particle is compressible it can be pressed to a point where it will not interfere objectionably with the reading, and yet, the crushing stresses will not be imparted to the indicator. Thus, the tool has rugged characteristics, and still has facilities for producing an extremely accurate reading.

I claim:

1. In a measuring instrument of the class having. a frame with spaced sides, aligned anvil and plunger members carried thereon at respective sides, and an indicator associated with the plunger; thenovel arrangement wherein the indicator has an actuating part arranged to move with the plunger'but not be moved by the plunger when the latter approaches the work, and there are means operatively connected with the plunger to move it, said means being secured to the frame only on the anvil supporting side of the frame, whereby the reactions on the frame, incident to forcing the plunger toward Work positioned between the sides, will not tend to separate the sides of the frame.

2, Ina measuring instrument of the class described, a frame having a pair of spaced arms substantially rigid therewith, an anvil on one of the arms, a micrometric measuring device including a feeler mounted on the other arm for movement toward and away from the anvil to measure work embraced by the feeler and anvil, an operating lever pivoted to the arm of the frame which carries the anvil, and a link connecting the lever to the feeler, whereby the feeler may be brought into forcible engagement with said work.

3. A micrometer having in combination, an indicator, a frame therefor, a work engaging stem slidably mounted in one portion of the frame for actuating the indicator, said indicator having an actuating part that moves with the stem but is not moved thereby as the stem approaches the work, an anvil in alignment with the stem, and carried by another portion of the frame for engagement with work opposite the stem, and means for moving the stem toward the anvil, said means being connected with the frame on the anvil carrying portion of the frame only, whereby the operation of said means will not tend to substantially force the anvil out of position with respect to the indicator irrespective of the magnitude of force applied to said means.

4. A measuring instrument having in combination a yoke-type frame, aligned fixed and movable measuring membersmounted on opposite arms of the yoke, indicating means operatively connected with the movable member, a handle connected with and extending from the yoke arm ofv the frame which carries the fixed measuring member and in a direction substantially normal to the axes of said measuring members, a finger grip bar pivotally mounted on the handle adjacent the last mentioned yoke arm, operating means connecting the grip bar to said movable member for moving the movable membertoward the fixed member, the points of connection between the operating means and the finger grip bar and movable member lying substantially in a plane which is coincident with the axes of said fixed and movable measuring members.

5. In a micrometer, having a frame with spaced parts, aligned fixed and movable measuring mem bers carried respectively on said parts for engagement with the work, indicating means operatively connected with the movable member, operating means for moving the movable member toward the fixed member, said operating means being pivotally mounted on the part of the frame which carries the fixed member, and connecting means pivotally secured to the operating means and movable member in a plane coincident with the axes of said measuring members.

WALTER A. BOH'N. 

